The present invention relates to a crankshaft rotational support arrangement for an internal combustion engine.
EP 885 354 B1 discloses a crankshaft rotational support arrangement by which the crankshaft is rotatably supported by bearings arranged in a spaced manner from one another. The bushings are arranged between the bearing blocks and the bearing covers. A bearing cover and a bearing block together form a single castable unit. Moreover, the bearing cover is provided with side extending projections which are connected by stiffening elements to one another along the longitudinal extent of the motor on both sides of the crankshaft. Bearing blocks, bearing covers, and the stiffening elements initially form a unit for casting purposes. To effect the installation of the bushings, the bearing blocks and the bearing covers are separated from one another out of the cast unit by separation along separation interfaces lying in a diametrical plane of the crankshaft. The bearing blocks, the bearing covers, and the stiffening elements are cast as hollow items as a consequence of which it is necessary in the casting of each such component that a core be formed which must subsequently be removed, after the casting operation, through the various openings present in the cast unit. It can be readily appreciated that the removal of these cores engenders a relatively high work effort. The hollow apertures which remain after the removal of the casting cores therefrom can be used, to be sure, as guide paths for lubrication oil but, in such event, all openings used for the removal of the casting material must be closed in a relatively time consuming work process and even the slightest traces of casting sand, if not removed, will be entrained in the lubrication oil circuit and will necessarily lead to severe motor damage.
The present invention provides a bending resistant arrangement of the bearing blocks and the bearing covers of a crankshaft rotational support which can be fabricated with a relatively low work effort.
A high stiffness, or resistance to bending, is achieved with the arrangement of the present invention by the use of side projections of the bearing blocks, which have open profiles as viewed in section, and side stiffening elements, without necessitating an unfavorably large work effort to clear casting material from the cast crankshaft rotational support.
The use of side projections having an H-shaped profile provides good stiffness with respect to the main axes of the projections and, at the same time, permits easy removal of the casting sand following the casting process.